3.5.6
Other
Problem – The heat pump runs and runs but never stops
Cause
Troubleshooting
Remedy
1. Air in the heating system. Listen for air in the heat pump and heating system.
Bleed the heating system according to the
installation instructions.
2. Changed conditions Have
you increased your heating
and/or hot water demand?
▪
If the heat pump has been dimensioned for a certain
demand and this demand is increased, the heat pump
might not be able to maintain the desired room tem-
perature.
▪
If hot water consumption increases, a larger propor-
tion of time is used to produce hot water, which
means less time for heat production.
If the heat pump cannot cope with the de-
mand, replace it with one with a higher
output or supplement it with a higher out-
put auxiliary heater.
3. Lack of refrigerant, not
enough refrigerant in the
system.
Using manometer apparatus and thermometer, check that
the unit’s overheating is correct for the specific refrigerant.
Follow the correct procedure (depending
on type of refrigerant) to add the correct
amount of refrigerant.
If there appears to be a leak in the refriger-
ant circuit, carry out leak tracing and any
necessary corrective action. If leak tracer is
not available, brush soap water on the sus-
pected leak and look for bubbles. Also
check for oil as this can come out from the
refrigerant circuit.
Problem – Runs on electric heating element
Cause
Troubleshooting
Remedy
1. Operating mode AUX.
HEATER is selected.
If this operating mode is selected, the auxiliary heater is
used for heating and hot water production, not the com-
pressor.
If AUX. HEATER mode is selected and you
no longer want it, change to AUTO, the
heat pump then controls both the com-
pressor and auxiliary heater.
2. The compressor cannot
run due to an alarm.
Check the alarm that is indicated in the display.
Rectify the problem and rest the alarm. See
3. The integral value has
reached the start level for
the auxiliary heater.
Check what the integral value is in the control system.
If the auxiliary heater is in operation be-
cause the integral value has counted down
to the start value, the computer reacts as it
should, see the Installation instructions for
further information.
4. Peak heat operation (anti-
legionella function) is run-
ning.
Check if the heat pump runs peak heat.
Peak heat operation occurs in connection
with hot water production with the set in-
terval. The compressor should then start to
produce hot water and 2 minutes later the
auxiliary heater starts. The compressor
must then stop and the stop temperature
be reached with only the auxiliary heater
connected. Take no corrective action.
5. The heat pump has stop-
ped on HIGH RETURN.
▪
Check what the MAX RETURN value is set at in the
heat pump’s control computer. It must be adjusted to
the unit’s maximum supply temperature and the sys-
tem’s delta temperature so that it does not cut at too
high a return temperature when the highest supply
temperature is transmitted.
▪
Check what the return line sensor shows. Is it a plausi-
ble/actual value? If not, take a resistance reading from
the sensors and check against the ohm table in Meas-
If the MAX RETURN value is not adjusted for
the system according to the troubleshoot-
ing window, adjust it.
If the sensor is defective, replace it.
Service Instructions
DHP-AQ
VMGFJ202
Danfoss Heating Solutions
28
